another dog working in law enforcement is holland. fox files met up with him and his handler, metropolitan transportation authority police officer doug joseph. this k-9 unit is helping to lead the fight against terrorism in the big apple. >> in the mta, what would he be sniffing for 12346789. >> here our primary concern is explosives on the transit system in the metro area. >> tell me how important dogs have become in the last several years to american security? >> what the dog lets us do is move around any place, any time. they are versatile and we are lucky to have them. >> in 2010 after the pentagon spent four years and $17,000 researching ied detection they announced that nothing is better than a dog. >> having a dog on point is very important and they have saved many lives. >> coming up, the unbreakababab >>> here at lackland air force base in texas, dogs aren't the only ones receiving training. so are military working dog handlers. >> i wanted to keep things, the longer you are with the dog the more he wants to work for you. >>